Vehicle jack



. 1,635, 7 July 12 1927 J. H. BURKHOLDER 39 VEHICLE JACK 2 sheets-sheet 1` Filed June 24, 1924 J' HBUEKHQLDEB.

@5% u YIM atroz e115 J. H. BURKHOLDER VEHICLE JACK Jury 12, 19127. n 1,635,397

Filed June 24, 1924 v2 sheets-sheet 2 Patented July 12, 1927.

UNITED STATES! yltaaxa ATENTT oFElcE.

JOHN H. fBURKHOLDER, V.AS1-I1l3.5.\TID, OHIO, ASSIGNOR 'EOV ELITE MANUFACTURING COMPANY, A PARTNERSHIP GOMPOSED OIFIOHN H. B'URKHOLDER, 1P. E. COUNTRY-' MAN,'AND E. L.KILHEFNER, OF ASHLAND, OHIO. v.

VEHICLE JACK.

Application med June 24, 1924. `serial No. 722,014.

My invention relates to an improvement in vehicle jacks, especially jacks ot' the double Screw type in which one litty screw telescopes within another and power is appliec to one of the screws to rotate and elevate and A vlower the same within a hollow standard of comparatively low height. In general my object is to provide etlicient means for this or any other type of screw jack whereby a lift screw will be automatically checked or .stopped whenelevate'd to its maximum and the screw will not be lett in anpunstable position or become disengaged from its support and collapse, and a further object is t0 provide a simple and effective stopping device adapted to be actuated directly by rotai tion of the screw without being subjected to l the longitudinal pull of the screw.

In the accompanying drawings, Fig. 1 is 20 a side elevation of a double screw, jack embodying' my invention, the screws'being elevated and near the end of their upward travel, and Fig. 2 is a sectional view ofthe same partsvin the same position but ina vertical plane at right angles to Fig. 1. Fig.

3 is a top view and horizontal section onV line 3 3 of Fig. 1. Fig. 4 is a'horizontal section of the jack on line 44 of Fig. 1. AFig. `5 is a perspective view of the lower end of the main lift screw. Figs. 6 and 7 are similar cross sections on line :1aof Fig. 2, Fig. 6

showing the stop member riding upon the screw thread and pressed outward, and Fig.

7 showing the stop member entered into the cam notch in the screw and in arresting engagement with the stop Ashoulder on the screw. y

The jack illustrated in the drawings comprises a tubular standard 2 whichis screw- 4 threaded internally at its upper end to rei ceive a main lift screw 3. A bevel gear 4 is pinned or keyed to the upper end of screw 3, and a sleeve member 5 is suspended from the upper end of screw 3 and gear 4 by a cross plate 7 which is detachably secured by screws to the arms 8-8 of the yoke-shaped upper end of sleeve 5. Gear 4 is adapted to be rotated by a bevel pinion 6 on a stub shaft 6 journaled in a lateral extension 9 of the yoke portion 10 of sleeve 5, and any suitable means may be used to rotate stub shaft 8.

Rotation of gear 4 and screw 3 causes these parts to ascend or descend,` and sleeve 5 is carried upwardly and downwardly with the `screwbut is'prevented from rotating by a pair of lugs 11 which'project laterally from the upper end of standard 3 and extend into channeled guideportions 12-12 of sleeve'5-,

Cross plate 7 has a central opening14 therein through which a second andsmaller screw 15 is adapted to extend, Vand this second screw is prevented from rotating by `apro- Ajection 16 on plate 7 extending into a longitudinal groove 17 inscrew vlVlainscrew 3 1s tubular to receive secondary screw 15,

.and the upperend of main screw 3 iis'provided with internal screw threads 18 to engage the external screw-threads on the 'secondary screwvand thereby raise or' lower the saine whenever the main screw is rotated. A 4differential travel is thereby imparted to the two screws, and if the rotation of main screw 3 is not checked` and stopped it will unscrew itself from the standard and the jack will collapse.

stopping device adapted to automatically prevent further rotation of main screw 3 when it has reached a predetermined height within standard 2. This device comprises a short bolt 20 and a spring of anyvsuitable opening in the side of standard 2 and rides constantly upon theV flat top of the spiral thread 19 of main screw 3 until the-lower end of the screw is raised ytothe top ofthe standard. Then bolt 20 is caused to ride inward on an eccentric portion 22 formed in the spiral thread itself until `the `bolt engages a squared shoulder 23 also formed vin y the same thread and extending into the bodyr of the screw below the base of the thread, thereby positively stopping further rotation of the screw and preventing all possibility of unscrewing the parts accidently. y I-Iowever, the bolt may be withdrawn temporarily by hand or a prying instrument to permitv i disassembly of the parts', but the lowering of the screw may be ett'ected without manipulatingor handling the bolt inasmuch as the reverse rotation of the screw will cause eccentric portion 22 on spiral thread 19 to v 75 I therefore provide a simple and effective y lpress the bolt outward Where it will constantly remain as long as it .rides upon the top 'of the screw thread. The bolt and spring are covered and protected `by the lchanneled gui-de portion 12 Yof sleeve 5 when the sleeve f is telescoped over the upper' part ofstandard 2, and when the jack is lowered and the parts completely drawn together the sleeve rests upon thebase of the standard and the two screws are telescoped lwithin each other andthe standard.

'The notch which forms shoulder 23 in screw 3 extends longitudinally of the screw,

fprefera'bl'yto the bottom of the screw, to

permit vaxial travel `of the screw while bolt rides-down the terminal cam portion22l ofthe' threadv and enters the notch and en-l gages the shoulder. Thus, the longitudinal movement Iand'lifting power of the screwis nottransmitted to the bolt, and damage and f breakage are avoided.`

What IIclaim' is :l I l. A vehicle jack, comprising. alst-andard, a

rotatable main screw having screw connection with said standard, a secondary lift 'screw mounted within said main screw, a

release thereof when the lift .screw is vertically-movable sleeve member suspended trom said main screw hav-ing a channeled portion engaging said standard-and adapted Vto prevent rotation `of said lsecondary screw,

means adapted to rotate sai-d main screw, a bolt extending 'throughl the sdeeotsaid standard and a supporting leal spring` for said bolt 1secured to the outer side of said standard opposite said kchanneled portion, and ak gear fixed thereto, a vertically movable sleeve suspended froml said ,gear having guide portions sleeved over' said standard, means on said standard and lift screw adapted to limit their relative Vinoven'ient, said sleeve normally covering` said means but permitting manual raised substantially to its limit. l

In testimony whereof I aHiX my signature. Y

JOHN BURKHQLDER. v 

